Even though virtual I/O technology is making it easier to move data from one system to another, there will still be a need to expand the physical I/O infrastructure to keep pace with growing requirements.
I came across this article by PLX Technology's Steve Moore describing the latest developments in PCI Express riser cards. These devices open up more room for expansion by allowing cards to be mounted parallel to the system board, rather than vertically.
Unfortunately, most riser cards come with only PCI or PCI-X interfaces, which aren't much good for the PCIe set. The latest designs, however, feature a PCIe-to-PCI-X bridge capable of translating between protocols.
Still, there are choices to be made as to which riser is appropriate for a given environment: passive vs. active cards, reverse-mode risers, and specialty cards for low-profile desktops and docks.
It just goes to show you that however much we try to simplify things in the virtual world, you can't neglect the physical.